In recent years, an electronic device including a large number of electronic circuit components has been used in many different fields.
A general method for assembling such an electronic device is so-called card edge connector connection in which an electronic circuit board including electronic circuit components is connected to an electronic device etc. through a connector. However, in this card edge connector connection, due to contact between metal parts at the time of connection, slight voltage difference occurs between the respective wires, and this difference further generates transient current.
This transient current may cause breakage of electronic devices etc. connected to the connector, and to cope with this problem, various countermeasures against the transient current have been created so as to be provided in the connection section.
FIG. 5 shows a connector connection mechanism as an example of the countermeasures against the transient current. In this mechanism, in both of a electronic circuit board 50, and a card edge connector 60 provided on the electronic device, wirings from connection terminals 53 and 63 are connected to the circuits 51 and 61 for making a short circuit, and the circuits 51 and 61 are further connected to ground via resistors 52 and 62 having a high resistance.
In this connector connection mechanism, when an electronic circuit board 50 is connected to a card edge connector 60 of an electronic device etc., transient current which has been generated due to voltage difference between the wirings connected to the connection terminals 53 and 63 flows into the circuits 51 and 61 connected to ground via the resistors 52 and 62, so as to prevent breakage of an electronic device etc.
Further, similarly, as a countermeasure against static electricity, Japanese Laid-Open Patent Publication Tokukaihei 05-36455/1993 (published on Feb. 12, 1993) discloses a connector connection mechanism of an electronic circuit board in which all of the connection terminals are respectively connected to resistors.
In the connector connection mechanism of an electronic circuit board disclosed in the foregoing publication, adjacent connection terminals of the electronic circuit board have different connection timings since the connection terminals are created to have different lengths from each other. Further, since a resistor having a high resistance is connected to a connection terminal subjected to the first connection, static electricity is discharged by the resistor having a high resistance before the remaining connection terminals are connected, thus preventing breakage of an electronic device etc. due to static electricity.
However, the foregoing conventional connector connection mechanisms of an electronic circuit board used as a countermeasure against transient current or a countermeasure against static electricity is not likely to be capable of completely preventing breakage of an electronic device etc.
Namely, in the foregoing connector connection mechanism of an electronic circuit board, the circuit 61 provided as a countermeasure against transient current or for other purposes is connected to ground via the resistor 62 having a high resistance, and provided not closely but distantly with respect to the connection terminal 63.
In this configuration, the generated transient current mostly flows into the circuit 61, but some of the current, though it will be only a little, still flows into wiring of the electronic device etc. in the card edge connector 60, thus failing to completely prevent breakage of the electronic device etc.
Further, also in the connector connection mechanism of an electronic circuit board used as a countermeasure against transient current disclosed in the foregoing publication, the adjacent connection terminals are made to be different in length so as to provide different connection timings to the adjacent connection terminals. However, this configuration has a problem such that the connector fails to effectively use all poles thereof.